FAQ — Virtual Machines

What is the difference between PortList and WholeIP?

Feature	PortList	WholeIP
Behavior	Only ports listed in externalPorts are exposed	All VM ports are exposed
Security	Fine-grained control, reduced attack surface	Requires OS-level firewall
Use case	Production, targeted services	Development, quick testing

warning

With WholeIP, you must configure a firewall inside the VM (iptables, nftables, ufw) to protect unexposed services.

vm-portlist.yaml

spec:
  external: true
  externalMethod: PortList
  externalPorts:
    - 22
    - 443

---

What images are available?

Hikube provides pre-configured Golden Images:

Operating System	Available versions
Ubuntu	22.04, 24.04
Debian	11, 12, 13
CentOS Stream	9, 10
Rocky Linux	8, 9, 10
AlmaLinux	8, 9, 10

Images are specified in the source.image.name field of the VMDisk resource, using the {os}-{version} format. For example: ubuntu-2404, debian-12, rocky-9.

---

How do I choose my instanceType?

Instances follow three families with different vCPU:RAM ratios:

Family	Prefix	Ratio	Example use
Standard	s1	1:2	Web servers, lightweight apps
Universal	u1	1:4	Business apps, databases
Memory	m1	1:8	Cache, in-memory processing

Available sizes range from small to 8xlarge. For example: u1.xlarge provides 4 vCPU and 16 GB RAM.

---

How do I add an extra disk?

First create a VMDisk resource, then reference it in your VMInstance:

data-disk.yaml

apiVersion: apps.cozystack.io/v1alpha1
kind: VMDisk
metadata:
  name: data-volume
spec:
  size: 100Gi
  storageClass: replicated

vm.yaml

apiVersion: apps.cozystack.io/v1alpha1
kind: VMInstance
metadata:
  name: my-vm
spec:
  instanceType: u1.large
  instanceProfile: ubuntu
  disks:
    - data-volume

---

How do I access my VM via SSH?

1. Inject your SSH public key in the VM manifest:

   vm-ssh.yaml

   spec:
     sshKeys:
       - "ssh-ed25519 AAAAC3... user@laptop"

2. Expose port 22 via PortList:

   vm-ssh.yaml

   spec:
     external: true
     externalMethod: PortList
     externalPorts:
       - 22

3. Retrieve the external IP address:

   kubectl get svc

4. Connect:

   ssh user@<external-ip>

note

The default username depends on the image: ubuntu for Ubuntu, debian for Debian, cloud-user for CentOS/Rocky/AlmaLinux.

---

How do I customize the VM at boot?

Use the cloudInit field to inject a cloud-init configuration in YAML format:

vm-cloudinit.yaml

spec:
  cloudInit: |
    #cloud-config
    packages:
      - nginx
      - htop
    users:
      - name: admin
        sudo: ALL=(ALL) NOPASSWD:ALL
        ssh_authorized_keys:
          - ssh-ed25519 AAAAC3... admin@company
    runcmd:
      - systemctl enable nginx
      - systemctl start nginx

Cloud-init runs at the first boot of the VM and allows installing packages, creating users, running commands, and more.

---

What is the difference between instanceProfile and instanceType?

Parameter	Role	Examples
instanceProfile	Loads the drivers and kernels adapted to the OS	ubuntu, centos, windows.2k25.virtio
instanceType	Defines the VM size (CPU/RAM)	s1.small, u1.large, m1.2xlarge

instanceProfile does not determine the OS image — that is defined in the VMDisk resource via source.image.name. The profile loads optimized drivers and kernels for the operating system. It is mainly useful for Windows (virtio drivers). instanceType sizes the CPU and memory resources allocated to the VM.